Mug S’mores

You will need

• 3 tbsp of self-raising flour
• 3 tbsp brown sugar
• 3 tbsp cocoa powder
• 3 tbsp flavourless oil
• 3 tbsp water
• a pinch of salt
• 1/2 tsp of vanilla extract
• 2 tbsp of cookie crumbs
• 3 marshmellows